Power system for a telecommunications network

ABSTRACT

A reliable, end-to-end power supply solution for components of a telecommunications network provides either a primary source or a backup source of electrical power at various telecommunications sites for reliable operation of telecommunications equipment. One subsystem of the power supply solution includes one or more proton exchange membrane type fuel cells and an energy storage device for storing DC electrical power produced by the fuel cells. Another subsystem includes one or more microturbine generators, one or more rectifiers for converting AC electrical power produced by the microturbine generators to DC electrical power, and one or more proton exchange membrane type fuel cells for producing DC electrical power. The power supply solution ensures that voice and data traffic is reliably handled by a telecommunications network in situations where commercial electric utilities fail to supply power at certain points along the network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of and claims priority toU.S. application Ser. No. 11/567,436, filed Dec. 6, 2006, and entitled“POWER SYSTEM FOR A TELECOMMUNICATIONS NETWORK,” which is in turn acontinuation-in-part of U.S. application Ser. No. 11/132,013, filed May18, 2005, and entitled “POWER SYSTEM WITH REFORMER,” the teachings ofwhich are incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND

Telecommunications service providers are increasingly concerned aboutmaintaining reliable network connections for both voice and datatransmissions. One particular area of concern is the maintenance of anadequate power supply at various sites along a telecommunicationsnetwork in order to ensure telecommunication equipment and facilitieshousing such equipment are functioning properly. For instance, at aremotely located telecommunications facility, such as a wirelesscommunication site (a “cell site”) utilizing a base transceiver system(station), the loss of power from a commercial electric utilitytypically results in a “dead area” where no wireless communications aresupported by the particular cell site. Even more critical is themaintenance of reliable and adequate power at a telecommunicationsexchange (switching office or subsystem) or a point of presence server,since power loss would result in the disabling of one or more telephoneswitches or critical gateways to the Internet, thereby affecting largevolumes of voice and/or data traffic.

Backup power supply for telecommunications network sites hastraditionally been supplied through diesel generators and the like, orlead-acid batteries. There are many disadvantages, however, to eachsolution. Among other things, diesel generators often emit large amountsof pollution during operation, and are also prone to mechanicalbreakdown. Furthermore, such generators and the accompanying fuelstorage device for supplying fuel take up significant amount of spaceper unit of power produced, making such devices unsuitable for use attelecommunications sites where space is critical. Lead-acid batteriesalso require significant maintenance over time, and may post a healthand environmental hazard due to the corrosive gases produced by thebatteries. Another drawback of lead-acid batteries is that suchbatteries suffer from a declining ability over time to hold a maximumamount of energy, which results in the useful lifespan of such batteriesoftentimes being shorter than a rated lifespan for the batteries.

SUMMARY OF THE INVENTION

A reliable, end-to-end power supply solution for a telecommunicationsnetwork is provided. In embodiments, the power supply solution serves aseither a primary source or a backup source of electrical power atvarious sites, providing levels of redundancy to ensure electrical powerdelivery to telecommunications equipment.

In one aspect, a power system of the present invention includes firstand second subsystems for providing DC electrical power. For instance,the first subsystem provides power to a wireless communication siteutilizing a base transceiver system, while the second subsystem providespower to a telecommunications exchange (switching office or subsystem)or to a point of presence server. The first subsystem includes one ormore proton exchange membrane type fuel cells and an energy storagedevice for storing DC electrical power produced by the fuel cells. Thesecond subsystem includes one or more microturbine generators, one ormore rectifiers for converting AC electrical power produced by themicroturbine generators to DC electrical power, and one or more protonexchange membrane type fuel cells for producing DC electrical power.

In another aspect, the power system of the present invention furtherincludes a third subsystem for providing DC electrical power, forinstance, to a multiple systems operator in a telecommunicationsnetwork. The third subsystem includes one or more proton exchangemembrane type fuel cells for producing DC electrical power and arectifier for converting incoming AC electrical power to DC electricalpower. For instance, the incoming AC electrical power may be supplied bya commercial electric utility.

Through the power system of the present invention, voice and datatraffic able to be carried along a telecommunications network from asource to a destination (e.g., end user to end user) in situations wherecommercial electric utilities fail to supply power at certain pointsalong the network.

Additional advantages and features of the invention will be set forth inpart in a description which follows, and in part will become apparent tothose skilled in the art upon examination of the following, or may belearned by practice of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The present invention is described in detail below with reference to theattached drawing figures, wherein:

FIG. 1 is block diagram illustrating the general relationship betweenvarious portions of a telecommunications network;

FIG. 2 is a schematic view of one embodiment of a first subsystem forproviding DC electrical power at a telecommunications network site;

FIG. 3 is a schematic view of one embodiment of a second subsystem forproviding DC electrical power at a telecommunications network site;

FIG. 4 is a schematic view of one embodiment of a circuit for providingDC electrical power for operating climate control units at atelecommunications network site;

FIG. 5 is a schematic view of one embodiment of a third subsystem forproviding DC electrical power at a telecommunications network site; and

FIG. 6 is a schematic view of another embodiment of a circuit forproviding DC electrical power for operating climate control units at atelecommunications network site.

DETAILED DESCRIPTION

Embodiments of the present invention relate to power system for atelecommunications network. One exemplary diagram of a simplified set ofsites or facilities that handle voice and/or data traffic along atelecommunications network is provided in FIG. 1. A plurality of cellsite facilities 1000, or wireless communication facilities that eachhave a base transceiver system, or BTS, (also referred to herein as abase station transceiver subsystem), are linked to a central facility2000 serving as a telecommunications exchange (also referred to hereinas a switching office or a network switching subsystem) or a point ofpresence (POP) server. The cell site facilities 1000 combine to providewireless communication coverage areas for mobile device users engagingin voice or data communications. The central facility 2000, as oneexample, carries out switching functions and manages communicationsactivity between the mobile device users serviced by the cell sites 1000and the public switched telephone network, or PSTN. Additionally, thecentral facility 2000 may act as a POP server, to control access to theInternet by devices users serviced by the cell sites 1000, and maycontain equipment for converting data signals to the proper protocol forsuch communications (e.g., TCP/IP). One or more central facilities 2000may also be connected along a telecommunications network to a multiplesystems operator, or mega site 3000. One example of a mega site 3000 isa facility that houses multiple telephone network switches and otherequipment for managing telecommunications network traffic.

One conventional standard for powering individual phone lines in ananalog telephone system is to provide 48 VDC to each line. This 48 VDCstandard remains largely in place for telecommunications networks thatinterface with wired customer lines, despite the fact that digitaltransmission technology is utilized in the network. Accordingly, certaintypes of telecommunications equipment, such as a BTS, are designed torun on a supply of 48-54 VDC, the amount above 48 VDC taking intoaccount voltage drop. The power system of the present invention includespower generating and storage components for supplying 54 VDC. In certainembodiments, the power system provides multiple 54 VDC components on onecircuit to provide redundancy should one component either fail or expendthe fuel supply to the component, or to act as a “bridge” to supplyadequate electrical current during a startup phase of another component.

Turning to FIG. 2, a first subsystem 100 provides a power supply for abase transceiver system (BTS) 102 and other electronics at a wirelesscommunication site 1000. For instance, the subsystem 100 may supplypower for a control device in the form of a programmable logiccontroller (PLC) 104 or microprocessor that manages the switchingbetween power supply components of the subsystem 100 during variousmodes of operation. Additionally, the subsystem 100 supplies power to atest power outlet 106 and to other facility devices, such as buildingair conditioning unit 108 for the cell site 100. The BTS 102 runs off ofDC electrical power, while an inverter 110 is provided in the portion ofthe circuit supplying power to the PLC 104, the power outlet 106 and theair conditioning unit 108 to provide these devices with AC electricalpower. In one suitable configuration, the inverter 110 takes 54 VDC atinput and outputs 240 VAC. For handling the interconnection between thevarious power generating/supplying components (as explained in moredetail herein) and the power consuming/delivering components, such asthe BTS 102, the PLC 104, power outlet 106 and air conditioning unit108, the first subsystem 100 employs a DC bus 112. For instance, acopper bus may be employed that can handle up to 300 amps. The DC bus112 ensures that a minimum amount (and desirably a constant amount) ofelectrical power is readily available for the power consuming/deliveringcomponents electrically connected with the bus 112. The BTS 102 iselectrically coupled with the DC bus 112 through a conductive line 113,while inverter 110 is located in-line on a conductive line 115 thatelectrically couples the PLC 104, power outlet 106 and air conditioningunit 108 with the DC bus 112.

The power generating/supplying components of the first subsystem 100electrically coupled with the DC bus 112 include a primary power sourcecomponent 114, a secondary power source component 116, a capacitivedevice 118 and a battery-type device 120. The primary power sourcecomponent 114 includes one or more proton exchange membranes (PEM) 122acting as fuel cells, as well as a hydrogen reformer 124 for supplyingthe PEM 122 with a supply of pressurized hydrogen gas. For instance, aset of high-pressure fuel storage tanks 126 contain liquid propane ornatural gas and connect with the hydrogen reformer 124 through a supplyline. The hydrogen reformer 124 converts the hydrocarbons in the fuelsource (e.g., propane, natural gas) to essentially pure hydrogen gasneeded by the PEM 122. The rate of hydrogen flow is controlled usingautomated pressure-controlled valves 128, with one valve heading each ofthe storage tanks 126. Each valve 128 enables the corresponding storagetank 126 to be sealed off (e.g., when a tank needs to be removed formaintenance or refueling). Downstream from the valves 128 is a commonmanifold 130 to more or less provide equal pressures in the storagetanks 126 with corresponding valves 128 in the open position. Extendingdownstream from the manifold 130 is a fuel line 132 or tubing thatcarries the fuel source to the hydrogen reformer 124. An in-lineautomated pressure-controlled valve 134 is included in the fuel line 132to selectively allow and disallow fuel flow from the storage tanks 126to the hydrogen reformer 124 depending on whether it is desired to havethe primary component 114 in operation. The PEM 122, in one arrangement,produces a 54 VDC output carried by conductive line 136 to the DC bus112.

In a similar arrangement, the secondary power source component 116utilizes one or more proton exchange membranes 138 acting as fuel cellscoupled with a fuel source. However, the PEM 138 of the secondarycomponent 116 receives hydrogen fuel directly from a set of liquidhydrogen storage tanks 140, so no hydrogen reformer is needed. Connectedwith the storage tanks 140 are automated pressure-controlled valves 142for each tank 140, as well as a common manifold 144 and a downstreamfuel line 146 containing an in-line automated pressure-controlled valve148. Because the PEM 138 operates with gaseous hydrogen, the fuel line146 and the environment surrounding the line 146 is of a configurationas to cause the liquid hydrogen from the storage tanks 140 to absorbthermal energy and undergo a phase change to a gaseous state within theline 146. Additionally, there may be a pressure drop through the valves142 to aid in the hydrogen phase change. Selective allowance anddisallowance of fuel flow from the storage tanks 140 to the PEM 138 iscontrolled by the in-line automated valve 148 depending on whether it isdesired to have the secondary component 116 in operation. As with theprimary component 114, the PEM 138 produces, in one arrangement, a 54VDC output carried by conductive line 150 to the DC bus 112.

The primary component 114 is designed to provide a DC power supplyduring a normal operating mode for the BTS 102 and other components,while the secondary component 116 provides power during a operating modeoutside of the normal operating mode (e.g., a backup mode when theprimary component 114 fails). Accordingly, the in-line automated valves134 and 148, for instance, under the control of the PLC 104, arecoordinated in their operation to be in the open position for when therespective component (primary 114 and/or secondary 116) is to beproducing electrical current. However, it should be understood that theroles of the primary component 114 and the secondary component 116 maybe reversed if desired. Alternatively, if a sufficient electricalcurrent demand is placed on the first subsystem 100 by the powerconsuming/delivering components, the primary and secondary components114 and 116 may operate simultaneously for a certain period of time tosimultaneously supply electrical current to the DC bus 112. Oneexemplary 54 VDC proton exchange membrane suitable for use in theprimary component 114 and the secondary component 116 is a modular,cartridge-based, proton exchange membrane I-1000 power modulemanufactured by Reli-On, Inc. of Spokane, Wash.

The capacitive device 118 preferably includes a plurality of capacitorsand the battery-type device 120 preferably includes a plurality oflithium metal polymer batteries (LMPs). Both the capacitors 118 and theLMPs 120 may be charged by an independent electrical power source, or inone arrangement, through the DC bus 112 during operation of the primarycomponent 114 or the secondary component 116. If the primary component114 fails to provide adequate electrical current to the DC bus 112 orotherwise is switched off (e.g., to refill the storage tanks 126), thecapacitors 118 and/or the LMPs 120 immediately provide adequateelectrical current by discharging to the DC bus 112 to bridge the timeperiod between the primary component 114 shut-off and secondarycomponent 116 operation at steady state (i.e., during the secondarycomponent 116 start-up phase). Breakers 152 and 154 may be placed inconductive lines 156 and 158 and under the control of the PLC 104 orother control device to selectively allow the capacitors 118 and theLMPs 120 to take up charge from or discharge to the DC bus 112 dependingon the desired mode of operation. For instance, in one preferredembodiment, the capacitors 118 provide DC electrical current during thetime it takes for the control device to open and close the in-lineautomated valves 134 and 148 and the fuel source to flow and generatesufficient electrical power with the respective primary or secondarycomponents 114 or 116. Thus, ideally the capacitor arrangement hassufficient discharge time which is able to accommodate the longest ofthese possible delays. Another function of these capacitors is that theyhelp smooth out the DC output of the PEMs 122 or 138 when more than onePEM is utilized in parallel with one another in the respective primaryor secondary components 114 or 116 in operation. Commonly, theelectrical output of whatever fuel cell is in use fluctuates. To makethis DC output consistent, the capacitors fill in for any dips inelectrical power providing a constant output level. One type ofcapacitor that is suitable for in the first subsystem 100 is a supercapacitor manufactured by Maxwell Technologies of San Diego, Calif. Theparticular number of capacitors 118 selected for use in the firstsubsystem is dependant on the specific discharge and load requirementsdemanded by the power consuming components of the first subsystem 100.The LMPs 120 are primarily utilized as a backup power supply when boththe primary component 114 and secondary component 116 fail to provideadequate electrical power to the DC bus 112. In this way, the LMPs 120allow the first subsystem 100 operator additional time to refill thefuel in the fuel storage tanks 126 and/or the liquid hydrogen storagetanks 140 while maintaining adequate electrical current for operation ofthe wireless communication site 1000.

Exemplary modes of operation of the first subsystem 100, under thecontrol of the PLC 104 or other control device, are now described. In afirst sequence of activity, breaker 160 in conductive line 136 isclosed, while breaker 162 in conductive line 150 remains open. At thesame time, breakers 152 and 154 in conductive lines 156 and 158,respectively, remain open and breakers 164 and 166 in conductive lines113 and 115 are closed to enable the BTS 102 as well as power consumingcomponents on conductive lines 115 to received electrical current fromthe DC Bus 112. In-line automated valve 134 is moved to the openposition (and storage tank valves 128 are likewise opened if not alreadyopened) to enable the fuel source to flow to the reformer 124 and thePEM 122 of the primary component 114 to produce electrical power forsupply through the conductive line 136 to the DC Bus 112. Upon a lowpressure condition being sensed in the in-line valve 134 indicative ofan insufficient fuel flow for continued operation of the primarycomponent 114 at the desired power level, a second sequence of activityis engaged.

In the second sequence, breaker 160 is opened and breakers 152 and/or154 are closed to supply electrical power from the capacitive device 118and/or the battery-type device 120 to the DC Bus 112 for uninterruptedoperation of the BTS 102 and other power consuming components.Additionally, in this second sequence, in-line automated valve 148 ismoved to the open position (and storage tank valves 142 if not alreadyopened) to enable the fuel source to flow to the PEM 138 of thesecondary component 116 to effect electrical power production by the PEM138 to supply through the conductive line 150 to the DC Bus 112.

The third sequence is initiated when the secondary component 116 movesfrom the start up phase to steady state operation in producingelectrical power for supply to the DC Bus 112. In the third sequence,breaker 162 is closed and breakers 152 and/or 154 are opened. This isdue to the fact that the secondary component 116 is meeting theelectrical current needs at the DC Bus 112, and the electrical powersupplied by the capacitive device 118 and battery-type device 120 is nolonger needed.

With reference to FIG. 3, a second subsystem 200 is illustrated forproviding a power supply for telecommunications electronics 202 or otherelectronics present at a central facility 2000. The second subsystem 200shares some common components with the first subsystem 100 as explainedin more detail herein. Generally, the second subsystem includes variouspower generating/supplying components such as a primary power sourcecomponent 204, a secondary power source component 206, a capacitivedevice 208, in much the same way as the first subsystem 100. These powergenerating/supplying components (and others described in detail herein)are coupled to a DC bus 210 to provide electrical power for powerconsuming/delivering components electrically connected with the bus 210.For instance, electrical current is drawn from the DC bus 210 by thetelecommunications electronics 202, as well as a PLC 212, power outlet214 and air conditioning unit 216 receiving AC power from an inverter218 (54 VDC input/240 VAC output, in one configuration) located in-lineon a conductive line 220 coupled directly with the DC bus 210.

The primary fuel cell based power source component 204 of the secondsubsystem 200 includes one or more PEMs 222 acting as fuel cells and acorresponding hydrogen reformer 224. In the particular embodimentillustrated in FIG. 3, a pair of PEMs 222 are depicted in series with anin-line automated pressure-controlled valve 226 positioned in a fuelline 228 between the reformer 224 and one of the PEMs 222. The in-linevalve 226, in this configuration, controls whether hydrogen gas issupplied to one or both of the PEMs 222 depending on the desired amountof electrical power to be generated and supplied to the DC bus 210 andto account for fluctuations in the electrical output of any one of thePEMs 222. A hydrocarbon-based fuel, such as natural gas or propane, issupplied to the reformer 224 via one or more fuel storage tanks 229 orthrough a commercial utility pipeline 230. Ideally, the primarycomponent 204 receives fuel from the pipeline 230 during normaloperation. However, when this source is not available, the fuel storagetank 229 provides adequate fuel for operation of the reformer 224 andthe PEMs 222 for a desired period of time. The PEMs 222 each produce a54 VDC output carried by conductive line 232 to the DC bus 210.

The secondary fuel cell based power source component 206 includes one ormore PEMs 234 receiving hydrogen fuel directly from a set of liquidhydrogen storage tanks 236. Automated pressure-controlled valves 238 areconnected with the set of tanks 236, as well as a common manifold 240and a downstream fuel line 242 containing an in-line automatedpressure-controlled valve 244. As with the primary component 204, thePEM 234 produces a 54 VDC output carried by conductive line 246 to theDC bus 210.

The PLC 212 controls the operation of a plurality of automated pressurecontrolled valves of the second subsystem 200. This includes the in-lineautomated pressure-controlled valves 226 and 244 of the first component204 and the second component 206, respectively, valves that control theflow of fuel from the storage tanks 229 and the pipeline 230 to thereformer 224, as well as other valves described in further detailherein. By controlling the fuel flow through the respective valves, thePLC 212 controls the sequence of operation of various powergenerating/supplying components of the second subsystem 200, includingthe switching from one power generating component to another component(or between alternate fuel supplies of one particular component) whenthe fuel supply is not adequate to maintain normal operating conditionsfor the component in question.

The valve arrangement upstream of the reformer 224 of the primarycomponent 204 includes a primary automated pressure-controlled valve 247regulating the fuel flow through the pipeline 230 moving towards thereformer 224, a secondary in-line automated pressure-controlled valve248 regulating the flow of fuel through a fuel line 250 receiving thestored fuel from the fuel storage tank 229, and a third in-lineautomated pressure-controlled valve 252 downstream of the primary andsecondary valves 247 and 248 regulating the flow through the main supplyfuel line 254 for the reformer 224. Interposed between all three valves(247, 248, and 252) at a T-junction between pipeline 230, fuel line 250and fuel line 254 is a surge tank 256 for absorbing pressureirregularities and thus minimizing any disruptive effects created by theopening and closing of the valves 247, 248 and 252. Additionally,upstream of the primary valve 246, a utility meter and manual shut-offvalve 258 integrated into the pipeline 230 allows for ceasing of theflow of fuel from the pipeline 230 to the primary component 204 withoutthe need for the PLC 212 to control fuel flow from the pipeline 230(i.e., without having to shutoff primary valve 247). The combination ofthe valves 247, 248 and 252 surrounding the surge tank 256, and the tank256 itself, is referred to herein as a fuel supply regulating mechanism260.

The second subsystem 200 also includes power generating/supplyingcomponents in the form of a microturbine 262 as well as an incomingutility power line 264. The electrical power output of the microturbine262 is fed via a conductive line 266 to a high voltage transfer switch268. The incoming utility power line 264 feeds electrical power past afuse cut-out transformer 270 (e.g., for ensuring that utility powersurges are not transmitted to the circuits of the second subsystem 200)to a main service entrance breaker 272 and onto the transfer switch 268.For instance, the incoming utility power may be three phase, 277/480 VACpower, while the power generated by the microturbine 262 may be threephase, 480 VAC power, as examples. The transfer switch 268 determineswhether the DC bus 210 receives utility supplied power or alternativelypower generated by the microturbine 262. The sequences of activity thatare affected by the transfer switch 268, and involve carrying out themodes of operation of the second subsystem 200, are explained in moredetail herein. Another conductive line 274 extends from the transferswitch 268 for carrying the supplied AC power from the switch 268 to a480/280 VAC transformer panel board 276. In one arrangement, thetransformer panel board 276 provides contact connections for threeconductive lines 278 to connect therewith. The conductive lines 278 eachcarry a portion of the electrical current fed into the transformer panelboard 276 from the conductive line 274. Located in-line on theconductive lines 278 is a rectifier 280 for converting the alternatingcurrent received from the transformer panel board 276 to direct currentfor supply to the DC bus 210.

The fuel supply for the microturbine 262 is a hydrocarbon-based fuel,such as natural gas or propane, provided via a set of high pressurestorage tanks 282 or via a commercial utility pipeline 284. Valves 286controlling the flow of fuel from the storage tanks 282 may be manuallyoperated shut-off valves or automated pressure-controlled valves. Theoutput of the valves 286 and the pipeline 284 both lead to a main supplyfuel line 287 directly connected with the microturbine 262. Theoperation of these valves 284 may be controlled by the PLC 212.Alternatively, the fuel supply regulating mechanism 260 integratedupstream of the primary component 204 of the second subsystem 200 may beimplemented with the fuel supply arrangement upstream of themicroturbine 262.

In a similar fashion to the first subsystem 100, various modes ofoperation for the second subsystem 200 (under PLC 212 or other devicecontrol) may be selected depending on the power consumption needs of thetelecommunications electronics 202, as well as the PLC 212 itself andany other consumption devices electrically coupled with the DC bus 210.It is contemplated that each power generating/supplying component mayoperate alone in supplying power to the DC bus 210 or in tandem withother components. For instance, under one set of rules, only a singlepower generating/supplying component is electrically connected with andsupplying power to the DC bus 210 at any given point in time, asregulated by the breakers and/or switches present in the variousconductive lines of the second subsystem 200. Alternatively, underanother set of rules, some temporal overlap is allowed whereby anadditional power generating/supplying component becomes electricallyconnected with the DC bus 210 during a startup phase of power generationfor that additional component, ensuring that adequate electrical currentis supplied to the DC bus 210. Under yet another set of rules, multiplepower generating/supplying components electrically may be connected withand supplying power to the DC bus 210 at the same time, if a heavy loaddemand is placed on the DC bus 210 by the power consuming components ofthe second subsystem 200. The breakers are also arranged in secondsubsystem 200 in much the same way as in the first subsystem 100. Morespecifically, the second subsystem 200 includes breaker 288 present in aconductive line 289 leading to the capacitive device 208 (e.g., aplurality of capacitors), breaker 290 present in conductive line 220between the inverter 218 and the power consuming/delivering components(e.g., PLC 212, power outlet 214, air conditioning unit 216), breaker294 present in conductive line 296 leading to the telecommunicationselectronics 202, breaker 298 present in conductive line 232 extendingfrom the PEM 222 output of the primary component 204, as well as breaker299 present in conductive line 246 extending from the PEM 234 output ofthe secondary component.

In one exemplary operational scheme for providing uninterrupted power tothe DC bus 210, utility power supplied by the utility power line 264 isused during normal operation, followed by power supplied by themicroturbine 262 when the utility power is not available, followed bypower supplied by the PEMs 222 of the primary component 204 when themicroturbine 262 is not available, followed by bridging power providedby the capacitive device 208 when the primary component 204 is notproviding adequate power, and subsequently followed by power supplied bythe PEM 234 of the secondary component 206. The appropriate breakers288, 298 and 299 are closed when the respective powergenerating/supplying components (capacitive device 208, primarycomponent 204 and secondary component 206) are providing electricalpower to the DC bus 210, and are opened otherwise, in the manner asexplained above for the modes of operation of the first subsystem 100.In a similar fashion, the transfer switch 268 is positioned to completea circuit with the utility power line 264 when power is supplied by theutility, and alternately to complete a circuit with the conductive line266 when the microturbine 262 when the same is operational and supplyingpower. When neither the utility power line 264 nor the microturbine 262is supplying power, the transfer switch 268 may be moved to close thecircuit with the power line 264 while the service entrance breaker 272is moved from the closed to the open position. This ensures thatsignificant electrical current is not drained from the DC bus 210 byflowing back up the electrical lines 278 and 274 to either themicroturbine 263 or the power line 264. With respect to the fuel supplyto the primary component 204, the secondary component 206, and themicroturbine 262, the valving structure of the second subsystem 200 iscontrolled by the PLC 212 in such a way that utility supplied fuel(i.e., through pipelines 230 and 284) is first used by the respectivepower generating components, followed by the stored fuel from thestorage tanks 229 and 282. Accordingly, in the case of the fuel supplyregulating mechanism 260 for the primary component 204, valves 247 and252 are opened, while valve 248 is closed, during typical powergeneration activity where utility supplied fuel is consumed. When thepipeline 230 cannot supply adequate fuel, valve 248 is opened, followedimmediately by valve 248 being closed and valve 248 to continueuninterrupted flow of fuel to the reformer 224. The surge tank 256 worksto maintain an even pressure through the main supply fuel line 254,especially during transitions between the utility fuel supply from thepipeline 230 and the stored fuel supply from the storage tank 229.Likewise, when the utility supplied fuel through pipeline 284 is notavailable for the microturbine 262, the valves 286 for the storage tanks282 move to the open position to enable the tanks 282 to supply fuel foroperation of the microturbine. It should also be understood that thefuel supply regulating mechanism 260 may be integrated into the mainsupply fuel line 287, as an alternative to the storage tank valves 286,to control the delivery of fuel to the microturbine 262 according to thedesired operational scheme for the second subsystem 200.

A dedicated back-up power generation system 300, for providing ACelectrical power to a cooling system 301 for the facility where thesecond subsystem 200 is located, is illustrated in FIG. 4. The powergeneration system 300 includes a power source component 302 includingone or more PEMs 304 acting as fuel cells, for generating DC electricalpower. Additionally, within the power generation system 300 is a set ofhydrogen fuel storage tanks 306 supplying fuel to the PEMs 304, a DC bus308 for receiving the electrical current output from the PEMs 304, aswell as an inverter 310 electrically coupled with the DC bus 308 toconvert the input DC electrical power from the DC bus 308 to output ACelectrical power for consumption by the cooling system 301. A fuel line312 extends from a header (not shown) connected with the storage tanks306 to a set of branch fuel lines 314 each connected with the input ofone of the PEMs 304. A primary in-line valve 316 is located in the fuelline 312 and a secondary in-line valve 318 is located in each of thebranch fuel lines 314. This arrangement controls overall powergeneration by the power source component 302 as well as the simultaneousoperation of selective PEMs 304, thereby controlling how much DCelectrical power is generated. Each PEM 304 outputs DC electrical powerto one branch conductive line 320 each electrically coupling with aninput feeder conductive line 322 coupled directly with the DC bus 308.An output feeder conductive line 324 coupled directly with the DC bus308 carries the electrical current to the inverter 310. The outputelectrical line 326 from the inverter 310 carries AC to a transferswitch 328, for alternating between AC supplied via a utility power line330, and when the commercial utility is not adequate, the AC supplied bythe power source component 302 through the inverter 310. The downstreamconductive line 332 extending from the transfer switch 328 carries theAC to the cooling system 301. Specifically, the cooling system 301includes a panelboard 334 which divides the AC for use by individual airconditioning units 336 electrically coupled with the panelboard 334.

Turning to the power supply arrangement for the mega site 3000, as shownin FIG. 5, a primary DC electric power supply source 400 and a set ofbackup DC electrical power generation units 402 function together toprovide uninterrupted power to a plurality of power distribution units(PDU) 404 of the mega site 3000. The power supply arrangement depictedin FIG. 5 may also be referred to herein as a third subsystem. The PDUs404 supply power to telecommunications equipment (e.g., routers,switches, servers) at the mega site 3000. In one exemplaryconfiguration, each PDU 404 requires 400 A, 48 VDC, with five PDUs 404demanding from a DC supply bus 422 an electrical power requirement of2000 A, 48 VDC (100 KW).

The power generation units 402 each include one or more PEMs 405 actingas fuel cells, for generating DC electrical power, a set of hydrogenfuel storage tanks 406 supplying fuel to the PEMs 405, a capacitor 408electrically coupled with a branch conductive line 410 extending fromthe output of each PEM 405, as well as a DC bus 412 with which eachpower generation unit 402 is electrically coupled. A fuel line 414extends from a header (not shown) connected with the storage tanks 406to a set of branch fuel lines 416 each connected with the input of oneof the PEMs 405. Each branch conductive line 410 electrically coupleswith an input feeder conductive line 418 coupled directly with DC bus412. An output feeder conductive line 420 coupled directly with the DCbus 412 carries the electrical current to the DC supply bus 422 withwhich the PDUs 404 are directly connected. The DC electrical powersupply source 400 is electrically coupled with the DC supply bus 422 viaa conductive line 423. Positioned on the conductive line 423 between theprimary DC electrical power supply source 400 and the DC supply bus 422is a back-feed diode 424. The back feed-diode 424 enables current toflow only in the direction leading from the primary DC source 400 to thebus 422, and not in reverse. This prevents electrical current to bedrained from the DC supply bus 422 by the primary DC source 400 when thesource 400 is not providing electrical power and operation of the backupDC electrical power generation units 402 is underway.

In operation, the primary DC electric power supply source 400 suppliesthe DC electrical power to the DC supply bus 422 and thus to the PDUs404 during normal operating conditions. When the PDUs 404 are notreceiving adequate power from the primary DC source 400, or otherwise ashutdown condition of the primary DC source 400 is noted, the hydrogenstorage tanks 406 are opened to each fuel line 414 and fuel beginsflowing to the PEMs 405 of each power generation unit 402 (or only oneunit 402 if DC power generation from that unit is adequate). DCelectrical power is then generated by the PEMs 405, which flows to theDC bus 412 and onto the DC supply bus 422 for consumption by the PDUs404. During the start-up phase for the PEMs 405 (generally a fewseconds), the capacitors 408, having been previously charged by theprimary DC source 400 during normal operating conditions, provide a DCdischarge to the DC bus 412 to ensure that the PDUs 404 receive adequateelectrical power until the PEMs 405 can provide full electrical power.

Turning to FIG. 6, a dedicated back-up power generation system 500 isillustrated for use at the mega site 3000 facility. In particular, thepower generation system 500 functions to provide AC electrical power toa cooling system 501 for the facility mega site 3000 facility. The powergeneration system 500 is similar to the power generation system 300 ofFIG. 4, expect that system 500 has another independent set of PEMs andfuel storage tanks coupled with an DC bus. The power generation system500 includes separate power generation units 502 for generating DCelectrical power. Each unit 502 is formed by one or more PEMs 504 actingas fuel cells, as well as a set of hydrogen fuel storage tanks 506supplying fuel to the PEMs 504. A DC bus 508 receives the electricalcurrent output from the PEMs 504 and an inverter 510 is electricallycoupled with the DC bus 508 to convert the input DC electrical powerfrom the DC bus 508 to output AC electrical power for consumption by thecooling system 501. Within each power generation unit 502, a fuel line512 extends from a header (not shown) connected with the storage tanks506 to a set of branch fuel lines 514 each connected with the input ofone of the PEMs 504. A primary in-line valve 516 is located in the fuelline 512 and a secondary in-line valve 518 is located in each of thebranch fuel lines 514. This arrangement controls overall powergeneration by the respective PEMs 504 as well as the simultaneousoperation of selective PEMs 504, thereby controlling how much DCelectrical power is generated by the particular power generation unit502. Each PEM 504 outputs DC electrical power to one branch conductiveline 520 each electrically coupling with an input feeder conductive line522 coupled directly with the DC bus 508. An output feeder conductiveline 524 coupled directly with the DC bus 508 carries the electricalcurrent to the inverter 510. The output electrical line 526 from theinverter 510 carries AC to a transfer switch 528, for alternatingbetween AC supplied via a utility power line 530, and when thecommercial utility is not adequate, the AC supplied by the powergeneration units 502 through the inverter 510. The downstream conductiveline 532 extending from the transfer switch 528 carries the AC to thecooling system 501. Specifically, the cooling system 501 includes apanelboard 534 which divides the AC for use by individual airconditioning units 536 electrically coupled with the panelboard 534, inthe same arrangement provided by the power generation system 300 of FIG.4.

As can be understood, the present invention provides an end-to-end powersupply solution for a telecommunications network, and portions of such anetwork. The Furthermore, it should be appreciated by people skilled inthe art that the present invention is not limited to what has beenparticularly shown and described above. Rather, all matter shown in theaccompanying drawings or described above is to be interpreted asillustrative and not limiting. Accordingly, the scope of the presentinvention is defined by the appended claims rather than the foregoingdescription.

What is claimed is:
 1. A power system for a telecommunications network,comprising: a first subsystem for providing DC electrical power to afirst telecommunications network location, the first subsystemcomprising a valving structure controlled by a programmable logiccontroller (PLC) that switches between a utility supplied fuel sourceand one or more stored fuel supply sources, wherein the first subsystemfurther comprises at least a first power source component and a secondpower source component, wherein the first power source componentcomprises: at least a first proton exchange membrane adapted to directlyreceive hydrogen fuel from the utility supplied fuel source or a firststored hydrogen fuel source, wherein the first power source component isoperable to produce DC electrical power during a normal operating mode,and wherein the second power source component comprises at least asecond proton exchange membrane adapted to directly receive hydrogenfuel from a second stored hydrogen fuel source coupled with a reformer,wherein the first stored hydrogen fuel source is separate from thesecond stored hydrogen fuel source, the second power source componentoperable to produce DC electrical power during a backup mode, an energystorage device, and a DC bus for interconnecting at least the firstpower source component the second power source component, and the energystorage device, in parallel, wherein the energy storage device isconfigured to operate during: (1) at least a startup phase of powergeneration of the second power source component, or (2) upon a lowpressure condition being sensed in an in-line valve with a fuel line ofthe second power source component, wherein the switching between thesecond power source component and the energy storage device when the lowpressure condition is detected for the second power source component ismanaged by the PLC, wherein the low pressure condition is indicative ofan insufficient fuel flow from the reformer coupled to the second storedhydrogen fuel source of the second power source component; and a secondsubsystem for providing DC electrical power to a secondtelecommunications network location, the second subsystem including atleast one microturbine generator operable to produce AC electricalpower, at least one rectifier operable to convert the AC electricalpower from the at least one microturbine generator to DC electricalpower, and at least one power source comprising at least one protonexchange membrane operable to produce DC electrical power.
 2. The systemof claim 1, wherein the first telecommunications network locationcomprises a wireless communication site utilizing a base transceiversystem.
 3. The system of claim 1, wherein the second telecommunicationsnetwork location comprises a telecommunications exchange or a point ofpresence server.
 4. The system of claim 1, further comprising a thirdsubsystem for providing DC electrical power to a multiple systemsoperator, the third subsystem including at least one power sourcecomprising at least one proton exchange membrane operable to produce DCelectrical power and an inverter for converting incoming DC electricalpower to AC electrical power.
 5. The system of claim 4, wherein the atleast one power source of the third subsystem comprises a first seriesof proton exchange membranes on a first circuit and a second series ofproton exchange membranes on a second circuit, the third subsystemfurther including at least one power distribution unit connected withthe first circuit and wherein the inverter is connected with the secondcircuit.
 6. The system of claim 1, wherein the second subsystem furtherincludes an energy storage device for storing the DC electrical power.7. The system of claim 6, wherein the energy storage device of thesecond subsystem comprises one or more capacitors.
 8. The system ofclaim 1, wherein the second subsystem further includes an inverter forconverting incoming DC electrical power to AC electrical power.
 9. Thesystem of claim 1, wherein the energy storage device of the firstsubsystem comprises one or more capacitors.
 10. The system of claim 1,wherein the at least one proton exchange membrane of the at least onepower source of the second subsystem comprises: one or more protonexchange membranes on a first circuit as well as one or more protonexchange membranes on a second circuit, the at least one microturbinegenerator and the at least one rectifier being connected to the firstcircuit, the second subsystem further including an inverter forconverting incoming DC electrical power to AC electrical power andconnected with at least the second circuit.